Following the recent cardiovascular and fracture risk safety concerns associated with the glitazones and the introduction of a new class of hypoglycaemic, it seemed timely to review the Formulary Advice for type 2 diabetes.
Blood pressure remains more important than blood glucose because tight blood pressure control was found to contribute to reductions in deaths from long term complications, strokes and serious deterioration in vision in the United Kingdom Prospective Diabetes Study (UKPDS).
Metformin remains the first line choice based on its glucose benefits and the reductions in cardiovascular events observed in (UKPDS).
Sulphonylureas are second line agents based upon their well known efficacy and safety profile compared to the emerging safety concerns associated with the glitazones and the unknown safety profile of the newer gliptins.
Patients should have hypoglycaemic drugs added if they continue to have symptoms of diabetes, or if all other cardiovascular risk factors arecontrolled while HbA1c remains suboptimal. Drugs can be substituted if the patient experiences adverse drug reactions.
- Metformin for all patients, titrate to maximum tolerated dose
- Add (or substitute) Sulphonylurea (gliclazide or glipizide) and titrate to maximum tolerated dose
- If either metformin or a sulphonylurea is not tolerated, add pioglitazone provided the patient does not have heart failure and is not at high risk of developing heart failure
- If either metformin or a sulphonylurea is not tolerated and the patient has existing heart failure or is at high risk of heart failure, add a gliptin (sitagliptin is the only available option at the time of posting although more agents are expected)
As a rule of thumb hypoglycaemics reduce HbA1c by approximately 1%. In patients who are unlikely to reach an optimal level through combined use of oral agents consideration should be given to earlier initiation of insulin.